Haul bodies have long been used to haul various bulk materials over relatively significant distances. Typical bulk materials include rock, sand, gravel, dirt, agricultural products, etc. Many haul bodies are capable of dumping bulk materials by elevating or pivoting at least a portion of the haul body. Common examples are rear dumping dump trucks and side dumping haul bodies mounted on trailers. One typical rear dumping dump truck has an aft-located end wall or tailgate that swings open as the body is elevated. A typical side dumping haul body is tilted in its entirety and in a lateral direction to a degree at which the payload spills over a sidewall and is expelled to the side of the haul body. Also typically, the payload may be selectively dumped to either the left or to the right of the side dumping haul body. Depending on conditions where the payload is to be dumped, either a side dumping haul body or a rear dumping haul body may be preferred. Where a side dumping haul body configuration is preferred, the haul body will typically include a partially enclosed structure consisting of a floor structure, two laterally opposed side panels and fore and aft located end walls. Such a haul body will typically have an open top. Although in many circumstances existing side dumping haul bodies have significant advantages over rear dumping haul bodies, existing side dumping haul bodies do have some disadvantages.
Side dumping bodies come in many shapes and sizes and generally are sized based upon payload density to provide desired axle loading. Typically, existing side dumping haul bodies are configured like an elongated tub where the sidewalls and floor are a single element. Generally, the sidewalls are angled to aid in the dumping process. Fore and aft located end walls cap the tub structure and which has no moveable panels, as opposed to a tail gate common to a typical dump truck. Commonly, pivoting the entire tub structure about a longitudinal axis dumps the load. Hydraulic cylinders typically provide the force necessary to pivot the tub structure. By selectively pinning the tub structure to a left or right axis, the tub structure can be pivoted about the pinned axis. The material in the tub structure is eventually dumped over a sidewall of the tub structure.
There are several disadvantages to a side dumping haul body with a rigid tub structure. The tub structure must often be pivoted to extreme angles to achieve a final angle large enough to allow the payload to overcome friction and slide from the haul body. However, pivoting the haul body to extreme angles may result in instability and the rolling of the entire side dumping haul body onto its side. This may happen when, for example, the center of gravity of a side dumping haul body and retained material shifts beyond the point of the outer tire of the transport vehicle, causing a roll moment which may lead to a rollover. Oftentimes, the maximum dump angle achievable by current tub type side dumping haul body designs is about 45°. Under certain conditions, this may be inadequate for full shedding of the payload.
To enhance the dumping of material out of the haul body, known tub type side dumping haul bodies generally have relatively shallow sidewalls. However, this leads to a length-to-capacity ratio that is large when compared to other types of dumping haul bodies. The extended length necessary to achieve particular hauling capacities also increases bending moments on the body while dumping.
Side dumping haul bodies with hinged movable sidewalls are also known. By incorporating hinged movable sidewalls, as opposed to the fixed tub design as described above, a side dumping haul body may have vertically disposed sidewalls, decreasing the length-to-capacity ratio. However, these hinges are typically along the upper or lower edges of the sidewalls. There are several disadvantages to such hinged sidewalls. For example, hinged, movable sidewalls may become damaged during loading or unloading. Sidewalls that are only hinged may move uncontrollably due to the force of the payload when the mechanism used to position the sidewall in the closed position is released. Bottom hinged sidewalls may interfere with the position of materials that have been dumped. This type of sidewall may also be difficult to raise back into the closed position. Top hinged sidewalls may swing uncontrollably when the dumping process is started, leading to reduced control of the dumping process. Top hinged sidewalls also may be difficult to return to the closed position, particularly if the haul body is not on level ground or material within the haul body is interfering with full closure.
Some known side dumping haul bodies use hydraulics to move sidewalls during the dumping process. However these systems also utilize hinges along the top or bottom edge of the sidewalls, and therefore share many of the shortcomings discussed above. Also known moving sidewalls systems require additional actuators and latches.
Accordingly, it would be desirable to provide a side dumping haul body where steep floor dumping angles can be achieved without a significant loss in stability. Similarly, it would be desirable to provide a side dumping haul body with movable sidewalls that are not hinged along the top or bottom edges of the sidewalls. It would also be desirable to provide a side dumping haul body with movable sidewalls, where separate latching operations would not be required to secure the sidewalls in the lowered or neutral position.